The poll by YouGov for the business campaign group London First comes as residents and families in the capital get used to the introduction of the scheme, which is designed to keep the dirtiest vehicles out of central London.

Diesel vehicles that do not meet Euro 6 standards and petrol vehicles that do not meet Euro 4 standards must pay £12.50 a day or face a fine.

Parents Isabele Adamson, 27, and Nick Adamson, 31, welcomed the charge. Buying lunch in Borough Market with their nine-month-old son hours after the measures came into effect, they admitted to having serious concerns about air pollution and the impact on their child.

“My husband has asthma, so we’re really concerned about Arthur developing asthma or his lungs not developing properly,” said Isabele. Although they supported the charge, they believed it was only “a small drop in the bucket” and were keen for the zone to be extended.